Pyrrolidone is particularly useful as an intermediate in the preparation of Nylon-4, in the preparation of N-methylpyrrolidone and N-vinylpyrrolidone which are useful as organic solvents, and in the formation of polymers which have certain specific properties.
Pyrrolidone has been prepared according to U.S. Pat. No. 3,095,423 in a liquid phase process comprising the simultaneous hydrogenation and hydrolysis of succinonitrile utilizing aqueous ammonia and hydrogen pressures of at least 500 psi, in the presence of a hydrogenation catalysts such as the oxides of ruthenium, palladium and platinum, Raney nickel and Raney cobalt, and the like. U.S. Pat. No. 3,781,298 also describes a single step process for preparing 2-pyrrolidone by hydrogenating succinonitrile in an aqueous solution in the presence of a Raney cobalt catalyst at pressures greater than 2000 psig. U.S. Pat. No. 3,644,402 discloses a two-step process for hydrolyzing and hydrogenating succinonitrile sequentially, wherein the hydrolysis reaction is conducted in aqueous ammonia and the hydrogenation in the presence of a nitrogen-containing basic organic solvent and a catalyst such as nickel-silica gel, palladium-carbon, Raney nickel, Raney cobalt, and the like, at pressures of from about 750 to 3000 psi. None of the processes of the prior art, however, teach the use of nickel boride as the hydrogenation catalyst as employed in the instant invention.